NetWorker: AUTHC fails with "unable to find valid certification path to requested target" in a round robin DC environment

• You are attempting to integrate AD over SSL (LDAPS) with NetWorker AUTHC.
• The process from KB NetWorker: How To configure LDAPS Authentication has been followed

• The configuration fails with:

ERROR [main] (DefaultLogger.java:222) - Error while performing Operation:
com.emc.brs.auth.common.exception.BRHttpErrorException: 400 . Server message: Failed to verify configuration CONFIG_NAME An SSL handshake error occurred while attempting to connect to LDAPS server: unable to find valid certification path to requested target

• You are using an "alias" for the AD server which connects to different DCs in a round robin configuration. 

The Certificate Authority (CA) is linked to the round robin alias Fully Qualified Domain Name (FQDN). The configuration attempts to bind the Secure Sockets Layer (SSL) to a specific server. 

For example, 'ad-ldap.amer.lan' may be a DNS round robin alias that redirects to multiple DC hosts in the environment. Collecting the certificate with openssl while using the alias returns the certificate for one of the hosts 'dc1.amer.lan' available through round robin

[root@nsrserver: ~]# openssl s_client -showcerts -connect ad-ldap.amer.lan:636
Certificate chain
0 s:/CN=dc1.amer.lan
   i:/DC=lan/DC=amer/CN=AUTH-CA01
-----BEGIN CERTIFICATE-----
**REMOVED**
-----END CERTIFICATE-----
---
Server certificate
subject=/CN=dc1.amer.lan
issuer=/DC=lan/DC=amer/CN=AUTH-CA01

If the certificate is imported to the JRE/NRE cacerts keystore using the round robin alias 'ad-ldap.amer.lan,' the configuration does not match the 'dc1.amer.lan' or any other server in the round robin configuration due to the name mismatch.

You can use a round robin alias in non-SSL Lightweight Directory Access Protocol (LDAP) connections. There is no requirement for SSL certificate to match the host alias of a specific address.
 
To use SSL authentication, the certificate alias must match the host that it is connecting to. Import the CA certificate for a specific DC, and configure NetWorker authentication to use only that server; optionally import all round robin certificates. If the original DC has issues, update the configuration to use another DC with an already imported CA certificate.

See: NetWorker: How to configure "AD over SSL" (LDAPS) from The NetWorker Web User Interface (NWUI)